The present invention is directed to new detergent-dispersants of high alkalinity useful as additives for lubricating oils and to a novel process for their preparation.
British Pat. No. 1,015,769 discloses the preparation of detergent-dispersants of high alkalinity by:
(1) sulfurization of a mixture containing an alkylphenol and a metallic alkylbenzene sulfonate, in a molar ratio of sulfonate to alkylphenol of between 0.01 and 1:1, and preferably between 0.01 and 0.05:1, of a C.sub.8 -C.sub.18 monoalcohol, an alkaline earth metal oxide or hydroxide and glycol; PA1 (2) precarbonation of the sulfurized mixture; PA1 (3) addition of an alkaline-earth metal oxide or hydroxide; PA1 (4) carbonation of the resultant mixture; and PA1 (5) thereupon elimination of the glycol and recovery of the resultant detergent-dispersant. PA1 (1) reacting sulfur, at a temperature of between about 100.degree. and 190.degree. C., with an alkylphenol bearing one or more C.sub.6 -C.sub.60 alkyl substituents in the presence of a dilution oil, an alkaline-earth metal alkylbenzene sulfonate of a molecular weight of more than about 300 and a T.B.N. less than or equal to about 170, a base derived from an alkaline-earth metal, and an alkylene glycol, the amount of alkylphenol used being between about 5 and 35 parts by weight per 100 parts by weight of total alkylphenol/alkylbenzene sulfonate mixture and the amount of alkylbenzene sulfonate being between 95 parts and 65 parts by weight per 100 parts by weight of alkylphenol/alkylbenzene sulfonate mixture; PA1 (2) precarbonating the resultant mixture at a temperature of between about 100.degree. and 250.degree. C., by means of carbon dioxide; PA1 (3) superalkalinizing and carbonating the resultant precarbonated mixture by means of a base selected from among alkaline earth metal oxides and hydroxides and carbon dioxide in the presence of an alkylene glycol at a temperature of between about 100.degree. and 250.degree. C.; and PA1 (4) eliminating the excess alkylene glycol and recovering the resultant detergent-dispersant of high alkalinity. PA1 (1) the sulfurization stage is carried out starting with an alkylbenzene sulfonate of a T.B.N. less than or equal to about 50 at a temperature of between about 120.degree. and 180.degree. C., and a pressure less than or equal to atmospheric pressure. This step can possibly be followed by a dehydration step at a higher temperature of between about 130.degree. and 185.degree. C., and preferably between about 150.degree. and 185.degree. C., at a pressure less than or equal to atmospheric pressure; PA1 (2) the precarbonation step is carried out at atmospheric pressure, at a temperature of between about 160.degree. and 185.degree. C.; PA1 (3) the superalkalinization-carbonation step is carried out at least once at a temperature of between about 120.degree. and 180.degree. C., at a pressure equal to or less than atmospheric pressure. PA1 A. for the sulfurization step: PA1 B. for the carbonation step: PA1 C. for the superalkalinization-carbonation step:
It has been found that while such a process made it possible satisfactorily to prepare detergent-dispersants containing high percentages by weight of alkaline-earth metal alkylphenates, it did not make it possible to prepare detergent-dispersants containing high percentages by weight of alkaline-earth metal alkylbenzene sulfonates. As a matter of fact, if a large amount of initial alkylbenzene sulfonate compared with the amount of alkylphenol was used, the mixture to be sulfurized and carbonated would have such a viscosity that any sulfurization and carbonation operation would be impossible. It would have been perhaps possible to solve this problem by adding large amounts of a C.sub.8 -C.sub.18 monoalcohol, which would then have presented serious drawbacks from an industrial standpoint with respect to the recycling of this monoalcohol in practically anhydrous form.
By the present invention, a new process has been provided which does not have the drawbacks of the prior art and which makes it possible to prepare novel detergent-dispersants having a base of alkylbenzene sulfonates and metal alkylphenates of a T.B.N. (Total Basic Number--A.S.T.M. Standard 2896) of more than 250.
It is, therefore, an object of the present invention to provide novel detergent-dispersants useful as additives for lubricating oils having a base of alkylbenzene sulfonates and metal alkylphenates.
It is also an object of the present invention to provide a novel process for the preparation of detergent-dispersants for use in lubricating oils.
It is also an object of the present invention to provide lubricating oils containing the novel additives of the invention.
Other objects of the present invention will be apparent to those skilled in the art from the present description.